diff --git a/Include/bltinmodule.h b/Include/bltinmodule.h
index 41c11cc..9ef7065 100644
--- a/Include/bltinmodule.h
+++ b/Include/bltinmodule.h
@@ -24,4 +24,4 @@
 
 /* Built-in module interface */
 
-extern object *getbuiltin PROTO((char *));
+extern object *getbuiltin PROTO((object *));